Precision studies of few-nucleon system dynamics

Abstract

Modern nucleon-nucleon interaction models can be probed quantitatively in the three-nucleon (3N) environment by comparing predictions based on rigorous solutions of the Faddeev equations with the measured observables. Proper description of the experimental data can be achieved only if the models are supplemented with additional dynamical ingredients: subtle traces of suppressed degrees of freedom, effectively introduced by means of genuine three-nucleon forces and effects of the Coulomb force. As an example of precision studies of 3N system dynamics, new generation measurements of the 1H(d→,pp) n breakup reaction at 130 MeV are considered. Large sets of high accuracy, exclusive cross-section and analyzing power data acquired in these projects contribute significantly to constrain the physical assumptions underlying the theoretical interaction models. Comparisons of the cross-section data with the predictions using nuclear interactions generated in various ways, allowed to establish importance of including both, the 3N and the Coulomb forces to strongly improve description of the whole data set. Discrepancies observed in reproducing the analyzing power data hint at still persisting incompleteness of modeling the 3N system interaction dynamics.